Fix warning in example

@@ -2,6 +2,7 @@
 
 
 ## 1.3.24
 ## 1.3.24
 
 
+- Fix warning in example
 - Format Java code
 - Format Java code
 
 
 ## 1.3.23
 ## 1.3.23

@@ -132,7 +132,7 @@ class _QrCodeWidget extends Widget {
     } catch (ex) {
     } catch (ex) {
       if (onError != null) {
       if (onError != null) {
         _hasError = true;
         _hasError = true;
-        this.onError(ex);
+        onError(ex);
       }
       }
     }
     }
   }
   }